81388833 has 8 divisors (see below), whose sum is σ = 108969696. Its totient is φ = 54033600.

The previous prime is 81388829. The next prime is 81388847. The reversal of 81388833 is 33888318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81388833 - 2² = 81388829 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81388633) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 55563 + ... + 57008.

It is an arithmetic number, because the mean of its divisors is an integer number (13621212).

Almost surely, 2^81388833 is an apocalyptic number.

It is an amenable number.

81388833 is a deficient number, since it is larger than the sum of its proper divisors (27580863).

81388833 is a wasteful number, since it uses less digits than its factorization.

81388833 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112815.

The product of its digits is 110592, while the sum is 42.

The square root of 81388833 is about 9021.5759709709. The cubic root of 81388833 is about 433.3661047536.

The spelling of 81388833 in words is "eighty-one million, three hundred eighty-eight thousand, eight hundred thirty-three".